Q = Question
A = Answer
Q: Will a fake can with the 9mm bore hole work with 5.56 nato?
A: Yes, so long as the muzzle thread pitch is correct for your firearm and the projectile diameter is smaller than the bore hole it is safe to use.
Q: Can I shoot 50 beowulf (50 caliber) through a standard fake can?
A: No, a 50 caliber is greater than the bore diameter so it is not safe to shoot as the projectile will hit the inside of the fake can.
Q: Is a crush washer better than a 0 ring for installing fake cans?
A: No the oring is better for timing teh fake cans is reusable